n = [[1, 2, 3, 4], [5, 6, 7, 8], [10, 11, 12, 13]]
print(n[0])  # [1, 2, 3, 4]
print(n[0][0])  # 7
print(n[0][1])  # 7
print(n[0][2])  # 7

print(n[1])
